Manufacture of lubricating oil



Patented May 5, 1936 UNITED STATES PATENT, OFFICE 2,040,057 MANUFACTUREOF LUBRICATING OIL No Drawing. Application February 25, 1933. Serial No.658,668

16 Claims.

This invention relates to the manufacture of lubricating oilcharacterized by a low pour test and having other desirable qualitiesincluding a desired green fluorescence.

The invention contemplates the preparation of mineral lubricating oilhaving'a reduced pour test and other desired qualities from lubricatingoil stocks, such as those derived from mixed base crudes and the like,by the addition to the lubricating oil of a pour-depressing material orwax crystal inhibitor. The invention particularly contemplates thepreparation of a suitable pour-1 depressing material from pitch formed.by subjecting carbonaceous bodies, such as the tarry residua resultingfrom the cracking of mineral oil, or the extracts resulting from thesolvent refining of mineral oil, to destructive heating or cracking,thereby producing a pitch containing constituents having the desiredpour-depressing and coloring characteristics. This pitch is then treatedwith a solvent for the purpose of extracting these desired.constituents, following which they may be added to the lubricating oilstock which is to be treated.

As a solvent extracting medium, the lubricating oil stock itself, or aportion thereof, may be used, in which case it may be of advantage tocarry out the solvent extraction step in the presence of a comminutedsolid catalytic material to facilitate the removal of undesiredimpurities.

Any solvent suitable for the purpose may be employed and may comprisesolvents selected from the aliphatic or aromatic hydrocarbons, or thecyclic hydrocarbons of the furan type. Such solvents might, therefore,include light petroleum fractions, aliphatic ketones, benzol, furfural,or mixtures of these solvents with each other or with other liquids, toproduce mixtures adapted to extract the desired constituents from thepitch.

advantageous feature of the pour-depressing material of our inventionresides in its ability to impart a desired green fluorescent color tolubricating oil stocks derived from certain crude sources, and which arenormally deficient in this respect. This desired green fluorescence ischaracterized by the oil having a red color when viewed by transmittedlight, and a green color when viewed by reflected light, and whichcharacteristics have become associated with certain grades oflubricating oils. a

Lubricating oil stocks derived from parafiin and mixed base crudescontain substantial amounts of wax and, therefore, have a relativelyhigh pour test unless a substantial amount of this wax is removed. Theremoval of this wax is usually accomplished by cold settling,filtration, or centrifuging. However, lubricating oil stocks, afterdewaxing by these processes, may still retain a substantial amount ofwax and, therefore, may have a pour test well above 0'F.' The removal offurther quantities of wax from these stocks in order to further reducethe pour test necessitates further processing.

On the other hand, the presenceof a certain amount of wax in lubricatingoils may be beneficial from the standpoint of producing a lubricatingoil having a suitable temperature-viscosity characteristic.Consequently, it is of advantage to add to the oil a material which willhave the effect of reducing the pour test or cold test to the desiredextent without the necessity of entirely removing the remaining wax.

The material of our invention is simply and readily prepared from oilrefinery waste materials by the employment of a procedure comprisingtreating steps which are more or less similar to those used in ordinarypetroleum refining operations.

Waste materials suitable for use in preparing the pour-depressingmaterial of our invention advantageously comprise cracked petroleum tar,sometimes referred to as pressure-tar, resulting from the liquid orvapor-phase cracking of mineral oil for the productionof motor fuels.Other suitable materials may comprise the extract material separatedfrom petroleum fractions, particularly lubricating oil fractions, duringthe refining of such fractions with solvents such as furfural, liquidsulphur dioxide, and the like. The polymerized material removed fromcracked naphtha by treatment with a catalytic adsorbent clay may also beutilized. i

We have found that the pour-depressing material produced from thesesources in accordance with the procedure of our invention possesses, inaddition to its wax crystal inhibiting properties, the ability to imparta desired green fluorescence to lubricating oils which are normallydeficient in this respect.

The preparation of fluorescent bodies and their beneficial efl'ect .whenadded to lubricating oil fractions is known in the prior art, but suchmaterials heretofore have been prepared from coal tar products orresidues which are known to be rich in aromatic bodies or constituentsof the desired character.

The raw materials, or oil refinery waste materials from which ourproduct is prepared, do not, in their original condition, contain thedesired constituents to any appreciable extent. If presing oil stock inthe proportion of about 4 to 10 ent to any appreciable extent, they areat least not readily recoverable from these waste materials by usualextraction procedures.

We have found, however, that by-subjecting these refinery wastematerials to substantial cracking whereby a high melting point pitch isformed, representing about 50% or 60% of the charge, such pitch containsthese desired bodies in substantial amount.

The preparation of these bodies from such waste carbonaceous materialsand their addition to lubricating oilstocks will now be described inmore detail. a

The waste carbonaceous bodies, such as a cracked petroleum tar, or asolvent extract obtained from the solvent refining of mineral oil, issubjected to cracking at temperatures of about 850 to around 1000 F. andunder pressures which may range from substantially above atmospheric to400 pounds or higher. The particular-temperatures and pressuresemployed, as well as the duration of the time to w ch the material issubjected to cracking conditions, will depend upon the nature of thematerial, but may advantageously be adjusted or regulated so as toconvert the charge into a residue, comprising, for example, about 60% ofthe charge. This residue, which is in the nature of a pitch, solid atroom temperature and having a ball and ring melting point of around 160to 180 F., contains the desired pour-depressing bodies. This pitch fromrecracked pressure tar or cracked extraction products of the characterdescribed is found to be primarily insoluble in mineral lubricating oil,but contains desirable oil-soluble pour depressant constituents inconcentrated form. The pitch is particularly free from objectionableoil-soluble material which imparts a darkening effect to palelubricating oils.

This pitch, while maintained in a fluid condition, as, for example, byheating to 200 or 250 4 F., is mixed with, or dissolved in, a suitablesol-- vent. The solvent advantageously comprisesv a portion of thelubricating oil stock to which the final pour-depressing and fluorescentmaterial is to be added. It may be mixed with this solvent mineral oilfraction in proportions varying from 5 to 50 volumes of pitch to 100volumes of oil.

To this mixture, a solid adsorbent catalytic material is added, rangingfrom about 10 pounds to 45 pounds per barrel of mixture. The catalyticmaterial may comprise a diatomaceous earth or fullers earth, or mayconsist of an acid-treated clay.

The mixture of oil and clay is then heated to temperatures of around 350to 400 F. in the presence of steam, if desired, and filtered while hot.The catalytic material, during this preceding operation, is believed toexert a polymerizing effect upon the undesired constituents of theextracted material, and which polymerized constituents are removed alongwith the clay in the form of a filter cake during the filteringoperation.

The resulting filtrate contains the desired extracted bodies which, whenadded to the lubricating oil stock, substantially depress the pour testof the oil as well as impart thereto the desired color characteristics.This filtrate, containing the extract, may then be added to thelubricatparts of filtrate to about 96 to parts of'lubrieating oil stockand the whole subjected to mixing.

For example, the ad tion of about '6 parts of this filtrate to 94--partsofa lubricating oil fraction derived from mixed base crude, having aSaybolt universal viscosity of around 300 seconds at F. and a pour testof 25 F., reduces the pour test to around 0 F.

While certain temperature and pressure conditions aswell as liquidproportions have been set for h in the foregoing example, the inventionis not restricted to these particular conditions since they may bevaried as desired, depending upon the lowed by contacting with clay. Itis contemplat-' ed, however, that the high melting point pitch fromwhich the pour-depressing materials are to be extracted may be addeddirectly to the main body of lubricating oil stock before this stock hasbeen subjected to contact filtration in the presence of clay. In thisway, only a single contact filtration'operation with clay will benecessary.

As already indicated, the pour-depressing and fluorescent bodiesdissolved from the high melting point pitch may be separated from thesolvent in which they are dissolved in order to .produce them insubstantially concentrated form. This desired, may be selectiveiyextracted with solvents of differing solvent concentrated material, if

capacity, or with relatively light or volatile solvents in order tosegregate the material into fractions, some of which may be segregatedin a substantially dry or powdery form. It has been found that thematerial in this latter form may also be added to lubricating oil stockswith equal effect.

Reference to cracked petroleum tar" in the appended claims includestarry residues formed during the usual liquid or vapor-phase crackingThe term extraction products is intended to include extracted materialsand polymerized odies,

tion withvarious solvent liquids, 'or by contacting these fractions withcatalytic or other treating agents.

Obviously many modifications and variations of the invention, ashereinbefore set forth, may be made without departing from the spiritand scope thereof, and therefore only such limitations should be imposedas are indicated in the appended claims.

We claim:

1. In the process of manufacturing mineral lubricating oil fromlubricating oil stock containing parafiin wax and deficient with respectto color characteristics, the method of reducing the pour test of theoil and imparting thereto a defluorescence which comprises substantiallycracking at high temperature and under superatmospheric pressure an oilrefinery residue selected from the group consisting of cracked petroleumtar, extraction products separated in the solvent refining of petroleumfracoil-soluble material from the pitch in a portion of the lubricatingoil stock to be treated, mixing of mineral oil for the production ofmotor fuel.

as already indicated, which are removed therewith acomminutedsolidadsorbent catalytic material, filtering the mixture to produce afiltrate containing hydrocarbon bodies extracted 4 from the pitch whichhave the desired pour-depressing and fluorescent characteristics and arefree from undesirable constituents, and mixing said filtrate with themain body of lubricating oil stock to produce a lubricating oil ofdesired characteristics.

2. In the process of manufacturing mineral lubricating oil fromlubricating oil stock containing paraflin wax and deficient with respectto color characteristics, the method of reducing the pour test of theoil and imparting thereto the desired green fluorescence which comprisessubjecting an oil refinery residue selected from the group consisting ofcracked petroleum tar, extraction products separated in the solventrefining of petroleum fractions, and extraction products separated fromadsorbent filters in the refining of petroleum fractions to substantialcracking at .a temperature of from about 800 F. to around 1000 F. andunder superatmospheric pressure to produce a high melting point pitchwhich is pri marily insoluble in mineral lubricating oil but containsoil-soluble constituents having the desired pour-depressing 'andcoloring characteristics, dissolving oil-soluble constituents from thepitch in the lubricating oil stock to be treated, mixing therewith acomminuted solid adsorbent catalytic material, heating the resultingmixture and filtering while hot to produce a filtrate comprisinglubricating oil having the desired cold test and fluorescentcharacteristics and free from undesirable constituents.

3. In the process of manufacturing mineral lubricating oil fromlubricating oil stock containing paraffin wax and deficient with respectto color characteristics, the method of reducing the pour test of theoil and imparting thereto the desired green fluorescence which comprisessubjecting an oil refinery residue selected from the group consisting ofcracked petroleum tar, extraction products separated in the solventrefining of petroleum fractions, and extraction products separated fromadsorbent filters in the refining of petroleum fractions to substantialcracking at teifier'atures of from about 800 F. to around 1000" F. andunder superatmospheric pressure to thereby produce a pitch which ispriniarily insoluble in mineral lubricating oil but contains oil-solubleconstituents having the desired pour-depressing and coloring character-'istics, dissolvingoil-soluble constituents from the pitch in a portionof the lubricating 011 stock to be treated, mixing therewith'acomminuted acidtreated clay, heating the mixture in the presence ofsteam to an elevated temperature not substantially exceeding 400 F.,filtering while hot to produce a filtrate containing hydrocarbon bodieshaving the desired characteristics and free from undesirableconstituents, and mixing said filtrate with the main body of lubricatingoil stock to produce a lubricating oil of desired characteristics.

4. The method of preparing a material adapted to reduce the pour test ofmineral lubricating oils and to impart thereto a desired greenfluorescence, which comprises subjecting an oil refinery residueselected from the group consisting of cracked petroleum tar, extractionproducts separated in the solvent refining of petroleum fractions, andextraction products separated fromadsorbent filters in the refining ofpetroleum fractions, to substantial cracking at high temperature andunder superatmospheric pressureto form a pitchy residue which isprimarily insoluble in mineral lubricating oil but contains oil-solubleconstituents having the desired pour-depressing and coloringcharacteristics, and separating said constituents from the pitch byextraction with a solvent.

5, The method of pr paring a material adapted to reduce the pour test ofmineral lubricating oils and to impart thereto a desired greenfluorescence, which comprises subjecting an oil refinery residueselected from the group consisting of cracked petroleum tar, extractionproducts separated in the solvent refining of petroleum fractions, andextraction products separated from adsorbent filters in the refining ofpetroleum fractions, to substantial cracking at high temperature andunder superatmospheric pressure to form a high melting point pitch solidat ordinary temperatures, 'which is primarily insoluble in minerallubricating oil but contains oilsoluble constituents having the desiredpour-depressing and coloring characteristics, mixing a mineral oilfraction with said pitch adapted to extract said constituents therefrom,heating the resulting mixture to effect extraction, and removing thesolvent liquid therefrom to produce the desired material in concentratedform 6. The method of preparing a material adapted to reduce the pourtest of mineral lubricating oils and to impart thereto a desired greenfiuorescence, which comprises subjecting an oil refinery residueselected from the group consisting of cracked petroleum tar, extractionproducts separated in the solvent refining of petroleum fractions, andextraction products separated from adsorbent filters in the refining ofpetroleum fractions, to substantial cracking at high temperature andunder superatmospheric pressure to form a pitchy residue which isprimarily insoluble in mineral lubricating oil but contains oil-solubleconstituents having the desired pourdepressing and coloringcharacteristics, mixing a'lubricating fraction of mineral oil with saidresidue and commingling therewith a comminuted acid-treated clay,heating the resulting mixture and filtering while hot to'removeundesired impurities and produce a filtratecontaining the desiredmaterial dissolved in the oil.

7. The method of preparing a material adapted to reduce the pour test ofmineral lubricating oils and to impart thereto a desired green fiuorescence, which comprises subjecting an oil refinery residue selectedfrom the group consistand filtering while hot to remove undesiredimpurities and produce a filtrate containing the desired materialdissolved in the oil.

8. The method of producing a pom point reducing agent for a minerallubricating oil, which comprises subjecting an oil refinery residueselected from the group consisting of cracked petroleum tar, extractionproducts separated in the solvent refining of petroleum fractions, and

, extraction products separated from adsorbent filters in the refiningof petroleum fractions, to substantial cracking at high temperature andunder superatmosphe'ric pressure..to reduce the material to a pitchsubstantially solid at atmos pheric temperatures which is primarilyinsoluble in mineral lubricating oil but which contains desiredoil-soluble pour-depressant constituents.

9. The method 01' producing a pour point reducing agent for a minerallubricating oil, which comprises subjecting an oil refinery residueselected from the group consisting of cracked petroleum tar, extractionproducts separated in the solvent refining of petroleum fractions, andextraction products separated from adsorbent filters in the refining ofpetroleum fractions, to cracking at temperatures of around 800 to 1000F. and under superatmospheric pressure to reduce the material to a highmelting point pitch representing a residuum in 'excess of by weight onthe weight of the original residue, said pitch being primarily insolublein mineral lubricating oil but containing desired oil-solublepour-depressant constituents in concentrated form.

10. The method of producing a pour point reducing agent for a minerallubricating oil, which comprises subjecting an oil refinery residueconsisting of the extraction product separated from adsorbent filters inthe clay vapor treating of cracked naphtha to substantial cracking athigh vtemperature and under superatmospheric pressure to reduce thematerial to a pitch which is primarily insoluble in mineral lubricatingoil but which contains desired oil-soluble pour-depressant'constituents.

11. The method of producing a pour point reducing-agent for a minerallubricating oil, which comprises subjecting an oil refinery residueconsisting of the extraction product separated in the solvent refiningof alubricating oil stock, to substantial cracking-athigh temperatureand under superatmospheric pressure to reduce the material to a pitchwhich is primarily insoluble in mineral lubricating oil but whichcontains desired oil-soluble pour-depressant constituents.

12. The method of producing a pour point reducing agent for a minerallubricating oil, which.

cracked petroleum tar, extraction products separated in the solventrefining oi! petroleum fractions, and extraction products separated fromadsorbent filters in the refining of petroleum fractions.

14. A lubricating oil of relatively low pour point comprising a blend ofa mineral lubricating oil of relatively higher pour point with a minorproportion of a highly concentrated pour point depressant obtained byrecracking at high temperature and under superatmospheric pressure apressure tar to a pitchy residue which is primarily insoluble in minerallubricating oil but in which oil-soluble pour-depressant constituentsare highly concentrated.

15. A lubricating oil of relatively low pour point comprising a blend ofa mineral lubricating oil oi relatively higher pour point with a minorproportion of oil-soluble constituents extracted from a pitch whlchisprimarily insoluble in the lubricating oil and obtained by substantialcracking at high temperature and under superatmospheric pressure of anextraction product separated from adsorbent filters in the clay vaportreating of cracked naphtha.

16. A lubricating oil of relatively low pour point comprising a blend ofa mineral lubricating oil of relatively higher pour point with a minorproportion of oil-soluble constituents extracted from a pitch which isprimarily insoluble in the lubricating oil and obtained by substantialcracking at high temperature and under superatmospheric pressure of anextraction product separated in the solvent refining of a lubricatingoil stock.

ROBERT E. MANLEY. HOWARD H. GROSS.

CERTIFICATE OF CORRECTION.

Patent No. 2,040,057. May 5, 1936.

ROBERT E. MANLEY, ET AL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,second column, line 67, and page 3, first column, lines 16 and 42-,claims 1, 2 and 3 respectively, after the word "fractions" insert a.comma; page 3, second column, line 58, claim 7, after "constituents"insert a comma; page 4, second column, line 9, claim 13, after"cracking? insert the words at high tempera.-

Signedangl sealed this 3rd day of November, A. D. 19:56.

Henry Van Arsda-le (Seal) Acting Commissioner of Patents.

